study of the parts & functions of neurons. what a neuron looks like
TRANSCRIPT
Study of the parts
&functions of
neurons
NEUROANATO
MY
WHAT A NEURON LOOKS LIKE
Cells are specialized to…1.) Receive information from the neurons that feed it.
2.) Process the information
3.) Pass on information to the next neuron.
3 MAIN TASKS OF NEURONS
Carries sensory information toward the brain & spine.What are your senses?
3 TYPES OF NEURONS:SENSORY NEURONS
Transport messages away from the brain to the muscles, organs and glands.
3 TYPES OF NEURONS:MOTOR NEURONS
aka the middle man
Sensory and motor neurons do not communicate directly with each other.
Found in the brain and spine
3 TYPES OF NEURONSINTERNEURONS
parts &
functions
Receives messages from incoming terminal branches of other cells
Passes message to cell body
PARTS & FUNCTION: DENDRITES
Contains the cell’s nucleus (life-support)
Assesses all messages & passes on info at the appropriate time
PARTS & FUNCTION: CELL BODY
Cell body sends the message down the axon
Moves info from cell body to terminal branchThis is a one way streetBrain; the axons are very shortLeg; they can reach 3 feet long
PARTS & FUNCTION: AXON
Layer of fatty tissue that insulates the axon and speeds up the impulse and protects the message
Covering on your headphones
PARTS OF THE AXON:MYELIN SHEATH
If myelin sheath deteriorates:
Communication to muscles
slows leading to eventual loss of muscle control aka, Multiple Sclerosis (MS)
Forms junction with next cell by releasing the message into the synapse
PARTS & FUNCTION: TERMINAL BRANCH
How neurons communicate!
!!!
Information travels along the axon electrochemically (chemical change causes an electric signal)
What are the messages?Neurotransmitters & hormones
ELECTROCHEMICAL COMMUNICATION
Dendrites send two types of messages to the cell body
If ‘excitatory’ messages outnumber ‘inhibitory’ messages, the cell reached absolute threshold
Now the cell body releases an impulse that sends the message down the axon
The impulse and the movement of the message is called ACTION POTENTIAL
HOW THE CELL BODY KNOWS WHEN TO SEND AN ACTION
POTENTIAL
Once the cell body releases an Action Potential, the message gets carried down the axon and ends at the terminal branches
HOW THE MESSAGE GETS ‘THERE’…WHERE?
While the neuron is waiting to receive a message, its called ‘resting potential’
The cell body processes the message and if absolute threshold is reached, the impulse is fi red.
Once the cell body fi res an impulse, there is no going back! ALL OR NOTHING PRINCIPLE
It fi res in the same direction every time (dendrites to terminal branches)
Once the cell body fi res, it needs time to reset; refractory period
Just because the signal is stronger doesn’t mean the message goes faster! How do we tell the difference between a tap and a
slap?
PARTS OF ACTION POTENTIAL
When an action potential reaches a terminal branch, it releases the message into the synapse
These neurotransmitters stimulate the dendrites on the next cell; the whole process starts over again
WHAT HAPPENS AT THE TERMINAL BRANCH?
MR. N GOES TO THE BATHROOM